The most accessible nuclear device for any terrorist would be a radiological dispersion bomb. This so-called 'dirty bomb' would consist of waste by-products from nuclear reactors wrapped in conventional explosives, which upon detonation would spew deadly radioactive particles into the environment. This is an expedient weapon, in that radioactive waste material is relatively easy to obtain. Radioactive waste is widely found throughout the world, and in general is not as well guarded as actual nuclear weapons.
In the United States, radioactive waste is located at more than 70 commercial nuclear power sites, in 31 states. Enormous quantities also exist overseas — in Europe and Japan in particular. Tons of wastes are transported long distances, including between continents (Japan to Europe and back).
In Russia, security for nuclear waste is especially poor, and the potential for diversion and actual use by Islamic radicals has been shown to be very real indeed. In 1996, Islamic rebels from the break-away province of Chechnya planted, but did not detonate, such a device in Moscow's Izmailovo park to demonstrate Russia's vulnerability. This dirty bomb consisted of a deadly brew of dynamite and one of the highly radioactive by-products of nuclear fission — Cesium 137.
Extreme versions of such gamma-ray emitting bombs, such as a dynamite-laden casket of spent fuel from a nuclear power plant, would not kill quite as many people as died on Sept. 11. A worst-case calculation for an explosion in downtown Manhattan during noontime: more than 2,000 deaths and many thousands more suffering from radiation poisoning. Treatment of those exposed would be greatly hampered by inadequate medical facilities and training. The United States has only a single hospital emergency room dedicated to treating patients exposed to radiation hazards, at Oak Ridge, Tenn.
A credible threat to explode such a bomb in a U.S. city could have a powerful impact on the conduct of U.S. foreign and military policy, and could possibly have a paralyzing effect. Not only would the potential loss of life be considerable, but also the prospect of mass evacuation of dense urban centers would loom large in the minds of policy-makers.